1. The Field of the Invention
The present invention generally relates to the field of dental treatment materials. More particularly, the invention relates to packaging materials for dental treatment systems that can be used to bleach or otherwise treat a patient's teeth.
2. The Relevant Technology
Virtually all people desire white or whiter teeth. To achieve this goal, people have veneers placed over their teeth or have their teeth chemically bleached. A common bleaching method involves the use of a dental tray that is custom-fitted to a person's teeth and that is therefore comfortable to wear. One type of customized tray is made from a stone cast representative of a person's teeth. Another is customized directly using a person's teeth as a template (e.g., “boil-and-bite” trays).
Non-customized trays and strips that can be placed over a user's teeth have also been used. Non-customized trays are generally provided in multiple sizes that approximate the shapes and sizes of a variety of users' dental arches, while strips can be folded around the dental arch and under the occlusal tooth surfaces so as to cover at least a portion of the tooth surfaces of the dental arch.
A dental bleaching composition is often supplied in a separate container (e.g., a syringe or tube) from which it can be dispensed into the dental tray prior to placing the tray over the person's teeth. Alternatively, some dental bleaching trays and dental bleaching strips are provided pre-filled and/or pre-coated with a dental bleaching composition.
One disadvantage of pre-filled dental trays is that the dental bleaching compositions are typically sealed within packaging containers that are not completely impervious to water and oxygen molecules. A typical example of an existing package includes a foil or other peelable cover sealed over a rigid plastic support layer. Although the foil peelable cover may act as an effective barrier to water molecules, existing rigid plastic support layers are much less effective in preventing diffusion of water molecules therethrough over time. These existing packaging systems allow a small amount of water to be diffused across the plastic barrier, which can cause the bleaching compositions to eventually lose potency, particularly when stored at room temperature.
Typically water diffuses out of the dental treatment composition and across the plastic support layer of the packaging container, resulting in a dried out and ineffective treatment (e.g., bleaching) composition. Loss of water can decrease stability, resulting in decreased bleaching ability over time. In addition, diffusion of oxygen and water can also reduce stability since it is believed that peroxides release oxygen and water upon decomposition, and the ability of released oxygen and water to diffuse out of the package can shift the equilibrium toward increased peroxide decomposition.
Because of these disadvantages, it is recommended that many pre-filled bleaching systems be stored in a refrigerated environment prior to use. Refrigerated storage increases the stability of peroxide bleaching agents, thereby extending the shelf life of the packaged product. Such storage is often impractical, particularly for dental treatment systems intended for over-the-counter sale where refrigerated shelving may not be available practical.
It would be an improvement in the art to provide a pre-filled pre-packaged dental treatment system including a sealed packaging container that is substantially impervious to water molecules in order to thereby improve shelf life of the dental treatment composition (e.g., bleach).